1. Technical Field
The present invention relates to image-capturing units that capture image information from documents, and to image-capturing apparatus furnished with such image-capturing units.
2. Description of the Related Art
Recent years have seen demands for the speed at which scanners capture information to be made faster. To make the capturing speed faster while acquiring satisfactory images requires a light source with an increased quantity of light.
However, the light sources, such as xenon lamps, often used for scanners generate an increased quantity of heat when providing an increased quantity of light. A consequent problem that arises is that heat from the light source deleteriously deforms the mirrors and other optical components.
Furthermore, a unit frame on which the optical members are supported has been composed of a synthetic resin in order to reduce the weight of the unit frame. The unit frame has thus been integrally molded by a technique of pouring an aqueous synthetic resin into a mold. When mirrors are located below a lens as in the case of the unit shown in FIGS. 1 and 2 of Japanese Unexamined Pat. App. Pub. No. H09-66915, a fixing member for the mirrors needs to be formed below a fixing member for the lens. This complicates the shape of the mold. Moreover, if only the upper side of the frame is open and the frame must be extracted from the mold through this opening, the mold-extraction direction needs to be taken into account. This further complicates the shape of the mold. In particular, the level of complexity of the shape of the mold increases with decreasing distance to the bottom the frame; that is, the level of complexity increases consistently with the distance from the opening in the unit. This reduces molding accuracy. Thus, if the mirrors are fixed to the bottom of the unit, the positional accuracy of the mirrors decreases. To solve this problem, an adjustment mechanism for the mirrors may be provided. However, this may increase the number of parts required and the number of assembly steps, sharply increasing costs.